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Firefox Developer Edition Changelog

What's new in Firefox Developer Edition 126.0b7

Apr 29, 2024
  • New:
  • A simpler and more unified dialog for clearing user data is now available.
  • In addition to streamlining data categories, the new dialog also provides insights into the site data size corresponding to the selected time range.
  • Enabled AV1 hardware decode acceleration on macOS for M3 Macs.
  • Changed:
  • For consistency with Firefox desktop and addons.mozilla.org, Firefox for Android's "add-ons" settings have been renamed to "Extensions".
  • Added "Linux" to Firefox for Android's User-Agent string to fix some website compatibility issues.
  • Developer:
  • Developer Information:
  • Added an option to disable/enable the Developer Tools' Split console feature
  • Web Platform:
  • Implemented URL.parse(). Unlike the URL constructor, which throws when parsing fails, the static URL.parse() method instead returns null.
  • The CSS zoom property has been enabled by default following a lot of web compatibility and standardization work in the CSSWG.
  • Added support for CSS Custom :state() and CustomStateSet.
  • Added support for Screen Wake Lock API.
  • Added support for IDBFactory.databases for enumeration of IndexedDB databases.

New in Firefox Developer Edition 125.0b6 (Mar 29, 2024)

  • New:
  • Firefox now prompts users in the US and Canada to save their addresses upon submitting an address form, allowing Firefox to autofill stored address information in the future.
  • Firefox has expanded its download protection and now more proactively blocks downloads from URLs that are considered to be potentially untrustworthy.
  • The URL Paste Suggestion feature provides a convenient way for users to quickly visit URLs copied to the clipboard in the address bar of Firefox. When the clipboard contains a URL and the URL bar is focused, an autocomplete result appears automatically. Activating the clipboard suggestion will navigate the user to the URL with 1 click.
  • Firefox now provides an option to enable Web Proxy Auto-Discovery (WPAD) while configured to use system proxy settings.
  • Users of tab-specific Container add-ons can now search in the Address Bar for tabs that are open in different containers. Special thanks to volunteer contributor atararx for kicking off the work on this feature!
  • It is now possible to highlight in PDFs.
  • Firefox now supports AV1 codec for Encrypted Media Extensions (EME).
  • Fixed:
  • Fix for MFSA 2024-15 is included in Firefox Desktop and DevEdition 125.0b3 builds and newer.
  • Changed:
  • In a group of radio buttons where no option is selected, the tab key now only reaches the first option, rather than every option being reachable with tab. The arrow keys navigate between options as they do when there is a selected option. This makes keyboard navigation more efficient and consistent.
  • Firefox for Android no longer includes the variant and extension of BCP47 in the Accept-Language header of HTTP requests for better interoperability with other browsers.

New in Firefox Developer Edition 123.0b2 (Jan 24, 2024)

  • Fixed:
  • When translating web pages, we are now also translating text in tooltips (i.e. titles) and text displayed in form controls (i.e. placeholder).
  • Changed:
  • Address bar settings can now be found in Firefox Settings' Search section
  • Developer:
  • The Network Monitor now supports saving a response body to disk through the Save Response As context menu item. This replaces the Save Image context menu item, which only supported saving images.
  • Web Platform:
  • We now implement linearRGB interpolation for SVG gradients, as well as the existing sRGB interpolation. You can choose which to use via the color-interpolation property.
  • Previously, SVG feImage elements that pointed to SVG content required the SVG document to have a root element that had non-percentage width and height values. Such content will now fall back to use the default replaced element values of 300px width and 150px height and the feImage will no longer fail to render.
  • By enabling Preload and Modulepreload support, Early Hints are now fully supported.
  • Audio echo cancellation can now be applied to microphone inputs when the audio output is redirected to another device with setSinkId().
  • Firefox now supports declarative ShadowDOM, providing developers greater flexibility and improved ergonomics when working with ShadowDOMs directly within HTML.
  • Unresolved:
  • Some machines with older AMD CPUs may see image thumbnails incorrectly render as all black in file dialogs. If this is the case, updating the graphics driver should address this issue.

New in Firefox Developer Edition 122.0b1 (Dec 19, 2023)

  • New:
  • Firefox now prompts Windows users to install the Microsoft AV1 Extension to enable hardware decoding support from about:support if not already installed.
  • Firefox now supports Voice Control commands on macOS systems.
  • Firefox now allows you to force-underline links in websites. This is useful for people with achromatopsia for example.
  • On Linux, Firefox now defaults to the Wayland compositor when available instead of XWayland. This brings support for touchpad & touchscreen gestures, swipe-to-nav, per-monitor DPI settings, better graphics performance, and more.
  • Note that due to Wayland protocol limitations, Picture-in-Picture windows require an extra user interaction (generally right-click on the window) or a shell / desktop-environment tweak. See bug 1621261 for related discussion and tracking, this post for a KDE configuration, and this extension for GNOME.
  • Firefox now includes a floating button to simplify deleting drawings, text, and images added in PDFs.
  • Developer:
  • Developer Information:
  • The Firefox Debugger now includes a new feature: an option to disable the debugger; keyword on the current page. This feature is accessible via a new checkbox in the Breakpoints side panel, labeled Pause on debugger statement, located next to the existing Pause on exceptions checkbox. By default, this option is enabled, meaning that the debugger statements are active unless manually disabled.
  • Web Platform:
  • The CSS text-indent property now supports the hanging and each-line keywords, offering more convenient paragraph layout for styles such as bibliographies, poetry, etc.
  • Firefox now supports text-wrap: balance, which can improve the appearance of short multi-line text blocks such as long headings or captions by harmonizing the line lengths.
  • Lazy loading iframes are now supported (<iframe loading=lazy>). Lazy loading iframes are only loaded when visible, so non-critical iframes can load later when needed to speed up initial page loads, reduce initial network usage, etc.
  • The :has() selector is now supported. This allows authors to match elements that has, or "anchors", at least one element matching its relative selector.
  • Supprt has been added for tail call elimination in WebAssembly language to improve support for functional languages.

New in Firefox Developer Edition 120.0b9 (Nov 10, 2023)

  • The User Activation API has now been added, allowing JavaScript to check if the user currently is or has been active with the page (clicking, etc) with navigator.userActivation.
  • Early Hints Preconnect, the informational status code 103, is now enabled. This allows servers to send resource Link headers before the final HTTP response and improves performance on servers using this feature. (read more)

New in Firefox Developer Edition 119.0b1 (Sep 28, 2023)

  • You can now see all open tabs from all windows.
  • If you sync open tabs then you will now see all tabs from other devices.
  • Browsing history is now listed and you can sort by date or by site.
  • As before, recently closed tabs are also listed in Firefox View.

New in Firefox Developer Edition 118.0b3 (Sep 1, 2023)

  • Automated translation of web content is now available to Firefox users! Unlike cloud-based alternatives, translation is done locally in Firefox, so that the text being translated does not leave your machine.
  • On Firefox for Android, printing page content from the browser or share menu is now available.
  • On Firefox for Android, pinned user shortcuts now open in an existing tab if it already has the same URL.
  • Web Audio in Firefox now uses the FDLIBM math library on all systems to improve anonymity with Fingerprint Protection.
  • The visibility of fonts to websites has been restricted to system fonts and language pack fonts to mitigate font fingerprinting in Private Browsing windows.

New in Firefox Developer Edition 117.0b4 (Aug 7, 2023)

  • New:
  • Firefox has added a new dom.event.contextmenu.shift_suppresses_event preference allowing users to disable Firefox forcing the context menu to appear when pressing shift+right-click on a webpage as it can sometimes cause undesirable outcomes on certain sites.
  • macOS users can now control the tabability of controls and links via about:preferences
  • Automated translation of web content is now available to Firefox users! Unlike cloud-based alternatives, translation is done locally in Firefox, so that the text being translated does not leave your machine.
  • Firefox for Android now supports pasting images into contenteditable & designMode elements. Previously, only plain text and HTML was supported.
  • Support for credit card autofill has been extended to users with the IT, ES ,AT, BE, and PL locales.
  • Changed:
  • Firefox does not show a screen sharing indicator on Wayland any more. It never worked as well as on other platforms and desktop environments typically provide sharing indicators already.
  • Developer:
  • Developer Information:
  • Web compatibility inspection has been enhanced with our new CSS compatibility tooltip in the Developer Tools Inspector. An icon is now displayed next to properties that could lead to web compatibility issues. When hovered, the tooltip indicates which browsers are not supported and displays a link to the MDN page for the property so the user can learn more about it.
  • Web Platform:
  • ReadableStream.from is now supported, allowing creation of a ReadableStream from an (async) iterable.
  • Support for improved CSS nesting is now enabled by default.
  • Firefox now supports RTCRtpScriptTransform
  • Firefox now supports the CSS properties math-style and math-depth and the font-size: math value.

New in Firefox Developer Edition 115.0b7 (Jun 19, 2023)

  • New:
  • Hardware video decoding enabled for Intel GPUs on Linux.
  • Migrating from another browser? Now you can bring over payment methods you've saved in Chrome-based browsers to Firefox.
  • The Tab Manager dropdown now features close buttons, so you can close tabs more quickly.
  • The Firefox for Android address bar's new search button allows you to easily switch between search engines and search your bookmarks and browsing history.
  • Fixed:
  • Windows Magnifier now follows the text cursor correctly when the Firefox title bar is visible.
  • Changed:
  • On Linux, middle clicks on the new tab button will now open the xclipboard contents in the new tab. If the xclipboard content is a URL then that URL is opened, any other text is opened with your default search provider. This feature can be turned off using browser.tabs.searchclipboardfor.middleclick in about:config.
  • For users with a Firefox Colorways built-in theme, the theme will be automatically migrated to the same theme hosted on addons.mozilla.org for Firefox profiles that have disabled add-ons auto-updates. This will allow users to keep their Colorways theme when they are later removed from Firefox installer files.
  • Undo and redo are now available in Password fields.
  • Developer:
  • Developer Information:
  • In web development, we rely on third-party libraries which you may not be interested in while debugging. These can be ignored. Ignoring them means that breakpoints will not get hit and they are skipped during stepping.
  • You can now choose to Hide ignore-listed sources in the Developer Tools source tree.
  • Web Platform:
  • WebRTC application developers can now specify a target in milliseconds of media for the jitter buffer to hold. Altering the target value allows applications to control the tradeoff between playout delay and the risk of running out of audio or video frames due to network jitter.
  • Change array by copy provides additional methods on Array.prototype and TypedArray.prototype to enable changes on the array by returning a new copy of it with the change.
  • The animation-composition property is now supported, allowing a declarative way to define the composite operation used when multiple animations affect the same property simultaneously.
  • The builtin editor now behaves similarly to other browsers with contenteditable and designMode when splitting a node, e.g. typing Enter to split a paragraph, and also when joining two nodes, e.g. typing Backspace at start of a paragraph to join the paragraph and previous one.
  • When a node is split, the builtin editor creates a new node after the original one instead of before, i.e. creates the right node instead of the left node.
  • Similarly, when two nodes are joined, the builtin editor deletes the latter node and moves its children to the end of the preceding node instead of deleting the former node and moving its child to start of the following node.
  • Added the URL.canParse() function to allow easy and fast checking if URLs are valid and parseable.

New in Firefox Developer Edition 115.0b1 (Jun 6, 2023)

  • New:
  • Hardware video decoding enabled for Intel GPUs on Linux.
  • Migrating from another browser? Now you can bring over payment methods you've saved in Chrome-based browsers to Firefox.
  • The Tab Manager dropdown now features close buttons, so you can close tabs more quickly.
  • Fixed:
  • Windows Magnifier now follows the text cursor correctly when the Firefox title bar is visible.
  • Changed:
  • On Linux, middle clicks on the new tab button will now open the xclipboard contents in the new tab. If the xclipboard content is a URL then that URL is opened, any other text is opened with your default search provider. This feature can be turned off using browser.tabs.searchclipboardfor.middleclick in about:config.
  • For users with a Firefox Colorways built-in theme, the theme will be automatically migrated to the same theme hosted on addons.mozilla.org for Firefox profiles that have disabled add-ons auto-updates. This will allow users to keep their Colorways theme when they are later removed from Firefox installer files.
  • Undo and redo are now available in Password fields.
  • Developer:
  • In web development, we rely on third-party libraries which you may not be interested in while debugging. These can be ignored. Ignoring them means that breakpoints will not get hit and they are skipped during stepping.
  • You can now choose to Hide ignore-listed sources in the Developer Tools source tree.
  • Web Platform:
  • WebRTC application developers can now specify a target in milliseconds of media for the jitter buffer to hold. Altering the target value allows applications to control the tradeoff between playout delay and the risk of running out of audio or video frames due to network jitter.
  • Change array by copy provides additional methods on Array.prototype and TypedArray.prototype to enable changes on the array by returning a new copy of it with the change.
  • The animation-composition property is now supported, allowing a declarative way to define the composite operation used when multiple animations affect the same property simultaneously.
  • The builtin editor now behaves similarly to other browsers with contenteditable and designMode when splitting a node, e.g. typing Enter to split a paragraph, and also when joining two nodes, e.g. typing Backspace at start of a paragraph to join the paragraph and previous one.
  • When a node is split, the builtin editor creates a new node after the original one instead of before, i.e. creates the right node instead of the left node.
  • Similarly, when two nodes are joined, the builtin editor deletes the latter node and moves its children to the end of the preceding node instead of deleting the former node and moving its child to start of the following node.
  • Added the URL.canParse() function to allow easy and fast checking if URLs are valid and parseable.

New in Firefox Developer Edition 113.0b8 (Apr 26, 2023)

  • Say hello to enhanced Picture-in-Picture! Rewind, check video duration, and effortlessly switch to full-screen mode on the web's most popular video websites.
  • Passwords generated in Firefox now include special characters, making them more secure.
  • Importing bookmarks from Safari or a Chrome-based browser? The favicons for those bookmarks will now also be imported by default to make them easier to identify.
  • The Windows GPU sandbox first shipped in the Firefox 110 release has been tightened to enhance the security benefits it provides.
  • A 13-year-old feature request was fulfilled, and Firefox now supports files being drag-and-dropped directly from Microsoft Outlook. A special thanks to volunteer contributor Marco Spiess for helping to get this across the finish line!
  • Mac users can now access macOS Services directly from the context menu.
  • On Windows, the elastic overscroll effect is now enabled by default, with two fingers scrolling on touchpad or scrolling on touchscreen, you will see a bouncing animation when scrolling past the edge of a scroll container.
  • AV1 Image Format files containing animations (AVIS) are now supported, improving Firefox' support for AVIF images across the web.
  • Websites that use window.print() can now be printed in Firefox for Android.
  • Firefox for Android now supports hardware accelerated AV1 video decoding by default with supported hardware or via fallback to software decoding.
  • Following up on the work already shipped on macOS and Linux in Firefox 110, GPU-accelerated Canvas2D is now enabled by default for Firefox for Android also.
  • Locale added: Tajik (tg)
  • Firefox 113 introduces a redesigned accessibility engine which significantly improves the speed, responsiveness and stability of Firefox for users of screen readers, as well as certain other accessibility software, east Asian input methods, enterprise single sign-on software and other applications which use accessibility frameworks to access information.
  • The Awesomebar result menu is now enabled for all users, allowing you to remove history results and dismiss sponsored Firefox Suggest results.

New in Firefox Developer Edition 112.0b3 (Mar 17, 2023)

  • New:
  • Right-clicking on password fields now shows an option to reveal the password.
  • Ubuntu Linux users can now import their browser data from the Chromium Snap package. Currently, this will only work if Firefox is not also installed as a Snap package, but work is underway to address this!
  • Do you use the tab list panel in the tab bar? If so, you can now close tabs by middle-clicking items in that list.
  • You've always been able to un-close a tab by using (Cmd/Ctrl)-Shift-T. Now, that same shortcut will restore the previous session if there are no more closed tabs from the same session to re-open.
  • Users on macOS, Linux, and Windows 7 can now use FIDO2 / WebAuthn authenticators over USB. Some advanced features, such as fully passwordless logins, require a PIN to be set on the authenticator.
  • Changed:
  • The deprecated U2F Javascript API is now disabled by default. The U2F protocol remains usable through the WebAuthn API. The U2F API can be re-enabled using the security.webauth.u2f preference.

New in Firefox Developer Edition 109.0b5 (Dec 21, 2022)

  • New:
  • Manifest Version 3 (MV3) is now enabled by default (MV2 remains enabled/supported). This major update also ushers an exciting user interface change in the form of the new Unified Extensions button.
  • Firefox builds in Spanish from Spain (es-ES) and Spanish from Argentina (es-AR) now come with a built-in dictionary that can be used with the Firefox spellchecker.
  • Changed:
  • On macOS, Ctrl or Cmd + trackpad or mouse wheel now scrolls the page instead of zooming. This avoids accidental zooming and matches Safari's and Chrome's behavior. If you would like to restore the previous zooming behavior, set the mousewheel.with_control.action and mousewheel.with_meta.action prefs to "3" in about:config.

New in Firefox Developer Edition 108.0b1 (Nov 30, 2022)

  • New:
  • Import maps, which allow web pages to control the behavior of JavaScript imports, are now enabled by default.
  • Firefox now supports properly color correcting images tagged with ICCv4 profiles.
  • Fixed:
  • The bookmarks toolbar's default "Only show on New Tab" state now also works correctly for blank new tabs. As before, you can change the bookmark toolbar's behavior using the toolbar context menu.
  • Changed:
  • Firefox now supports the WebMIDI API along with a new experimental mechanism for controlling access to dangerous capabilities.

New in Firefox Developer Edition 107.0b1 (Oct 19, 2022)

  • Improved the performance of the case when Microsoft's IME and Defender retrieve the URL of a focused document in Windows 11 version 22H2.

New in Firefox Developer Edition 106.0b6 (Sep 30, 2022)

  • The PDF viewer allows text writing, drawing and signature.
  • Swipe to navigate (two fingers on a touch pad swiped left or right to perform history back or forward) on Linux for users on Wayland.

New in Firefox Developer Edition 105.0b9 (Sep 19, 2022)

  • New:
  • Added an option to print only the current page from the print preview dialog
  • Fixed:
  • Firefox is less likely to run out of memory on Linux and also performs better towards the rest of the system when memory is running low.
  • On Windows, Firefox itself will be more likely to survive briefly running out of memory, even if individual tabs crash.
  • Touchpad scrolling on macOS was made easier by reducing unintended diagonal scrolling on the opposite axis of the intended scroll axis.

New in Firefox Developer Edition 104.0b1 (Jul 27, 2022)

  • Subtitles are now available for Disney+ in Picture-in-Picture.
  • The PDF viewer allows text writing, drawing and signature

New in Firefox Developer Edition 102.0b2 (Jun 1, 2022)

  • New:
  • Improved PDF reading in high contrast mode
  • Changed:
  • There is now an enterprise policy (StartDownloadsInTempDirectory) and an about:config pref (browser.downloads.start_downloads_in_tmp_dir) that will once again cause Firefox to initially put downloads in (a subfolder of) the OS temp folder, instead of the download folder configured in Firefox. Files opened from the "what should Firefox do with this file" dialog, or set to open in helper applications automatically, will stay in this folder. Files saved (not opened as previously mentioned) will still end up in the Firefox download folder.
  • Developer:
  • You can now filter style sheets in the Style Editor tab of our developer tools

New in Firefox Developer Edition 100.0b1 (May 3, 2022)

  • New:
  • We now support captions/subtitles display on YouTube, Prime Video, and Netflix videos you watch in Picture-in-Picture. Just turn on the subtitles on the in-page video player, and they will appear in PiP.
  • Picture-in-Picture now also supports video captions on websites that use WebVTT (Web Video Text Track) format, like Coursera.org, Canadian Broadcasting Corporation, and many more.
  • Spellchecker now allows multiple language dictionaries at the same time.
  • Hardware accelerated AV1 video decoding was enabled on Windows with supported GPUs (Intel Gen 11+, AMD RDNA 2 Excluding Navi 24, GeForce 30).
  • Scrollbars on Linux and Windows 11 won't take space by default. On Linux, users can change this on about:preferences. On Windows, we follow the system setting (System Settings > Accessibility > Visual Effects > Always show scrollbars). To change this just on Firefox, use the widget.windows.overlay-scrollbars.enabled pref from about:config.
  • Firefox now supports credit card autofill and capture in the United Kingdom.
  • Fixed:
  • Users can now choose the preferred color scheme for websites. Theme authors can now make better decisions about which color scheme Firefox uses for menus etc. Web content appearance can now be changed in about:preferences.
  • Beginning in this release, the Firefox installer for Windows is signed with a SHA-256 digest, rather than SHA-1. Update KB4474419 is required for successful installation on a computer running the Microsoft Windows 7 operating system. For more details about this update, visit the Microsoft Technical Support website.
  • Improve the fairness between painting and handling other events. This noticeably improves the performance of the volume slider on Twitch.
  • Changed:
  • Some websites might not work correctly in Firefox version 100 due to Firefox's new three-digit version number. You can read about it in our blog post here!
  • See the Mozilla Support article Difficulties opening or using a website in Firefox 100 for some possible workarounds you can use. You will also find instructions for reporting a broken website so that Mozilla can help fix the problem.

New in Firefox Developer Edition 99.0b1 (Mar 8, 2022)

  • New:
  • You can now toggle Narrate in ReaderMode with the keyboard shortcut "n".
  • Linux: GTK overlay scrollbars are now enabled on Nightly and early betas
  • Added support for search with or without diacritics in the PDF viewer

New in Firefox Developer Edition 96.0b1 (Dec 17, 2021)

  • New:
  • Significant improvements in noise-suppression and auto-gain-control, slight improvements in echo-cancellation
  • Significantly reduced main thread load
  • Fixes an issue where video intermittently drops SSRC
  • Fixes issue where WebRTC downgrades screen sharing resolution
  • Firefox will enforce the Cookie Policy: Same-Site=lax by default which provides a solid first line of defense against Cross-Site Request Forgery (CSRF) attacks.
  • Fixes video quality degradation in certain sites

New in Firefox Developer Edition 88.0b6 (Apr 2, 2021)

  • New:
  • Added content blocking, a collection of Firefox settings that offer users greater control over technology that can track them around the web. In 63, users can opt to block third-party tracking cookies or block all trackers and create exceptions for trusted sites that don’t work correctly with content blocking enabled.
  • WebExtensions now run in their own process on Linux
  • Firefox now warns about having multiple windows and tabs open when quitting from the main menu. The Save and Quit feature has been removed. You can restore your session by ticking the box for Restore previous session in the General → Startup options or by using Restore Previous Session in the main menu.
  • On macOS, WebGL power preferences allow non-performance-critical applications and applets to request the low-power GPU instead of the high-power GPU in multi-GPU systems
  • Improved Windows 10 integration: your Firefox theme now matches your OS Dark / Light mode
  • Faster tab switching in the majority of cases for our macOS users
  • Improved the reactivity of Firefox on macOS
  • Fixed:
  • Resolved an issue that prevented the address bar from autofilling bookmarked URLs in certain cases
  • Changed:
  • In the Library, the Open in Sidebar feature for individual bookmarks was removed
  • The option to Never check for updates was removed from about:preferences. You can use the DisableAppUpdate enterprise policy as a substitute.
  • The Ctrl+Tab shortcut now displays thumbnail previews of your tabs and cycles through tabs in recently used order. This new default behavior is activated only in new profiles and can be changed in preferences.
  • The build infrastructure of Firefox on Windows moved to the Clang tool chain, bringing important performance gains
  • Developer:
  • Developer Information:
  • Refreshed visual style of Developer Tools menus to improve navigation and consistency
  • The Dev Tools accessibility inspector is now enabled by default. This tool surfaces information exposed to assistive technologies on the current page, allowing you to check what’s missing or otherwise needs attention.
  • Added support for Web Components custom elements and shadow DOM
  • unresolved:
  • Quick Heal internet security software might crash 32-bit Firefox on Windows. A workaround is documented from this support article until a fixed version of Quick Heal is available.

New in Firefox Developer Edition 88.0b5 (Mar 31, 2021)

  • New:
  • Firefox will automatically look for client certificates in platform-specific storage on Windows and macOS by default when necessary.
  • Smooth pinch-zooming using a touchpad is now supported on Linux under Wayland.
  • Fixed:
  • Fixed an issue with Firefox for Android where video playing in fullscreen or picture-in-picture mode would not display correctly on sites using a desktop viewport.
  • Changed:
  • The Take a Screenshot feature was moved from the Page Actions menu in the url bar into a regular icon you can add to your toolbar from the customize menu.
  • FTP has been disabled in Firefox Release 88. The implementation is planned to be removed in Firefox 90.

New in Firefox Developer Edition 83.0b1 (Oct 20, 2020)

  • New:
  • WebRender is now activated on Intel Gen12 GPUs
  • There is now a "Print selection" context menu item.
  • Device sharing state indicator icons have been added to the system tray on Windows
  • Changed:
  • HTTP authentication prompt dialogs are now tab-modal instead of window-modal
  • Developer
  • Developer Information
  • You can now click on the "scroll" badge for scrollable elements to toggle highlighting of the overflow causing elements, which also have a new "overflow" badge next to them
  • Web Platform:
  • Added support for CSS conic gradients

New in Firefox Developer Edition 79.0b2 (Jul 1, 2020)

  • MacOS versions 10.9, 10.10 and 10.11 are no longer supported by Firefox. Users of these macOS versions are recommended to switch to Firefox ESR 78.x in order to continue receiving security updates.

New in Firefox Developer Edition 76.0b4 (Apr 13, 2020)

  • New:
  • Double-clicking on the Picture-in-Picture player window now puts it in fullscreen mode.
  • Warnings will now appear on saved logins if the same password was stored for a site which was subject to a website breach.
  • Improvements to password generation and saving to work with many sites which previously didn’t.
  • Changed:
  • Accessing saved passwords in about:logins on Windows and macOS now requires the user to authenticate with their operating system if no master password is set.

New in Firefox Developer Edition 74.0b3 (Feb 14, 2020)

  • New:
  • Firefox users can now import profile data from Edgium on Windows and Mac
  • A New Container Tab menu can now be opened with right click on the new tab button. In addition, an option to require a container tab to be selected when the new tab button is clicked is available.
  • Changed:
  • The OS compositor has been enabled for macOS when WebRender is enabled
  • On Windows, Ctrl+I can now be used to open the Page Info window instead of opening the Bookmarks sidebar. Ctrl+B still opens the Bookmarks sidebar.
  • DNS over HTTPS (with Cloudflare as the DNS resolver) will begin to roll out for users, turning the option on by default for users in the United States. For an alternate DNS service, users can select NextDNS via the Network Settings dialog in Preferences.

New in Firefox Developer Edition 73.0b (Jan 20, 2020)

  • New:
  • Added support for setting a default zoom level applicable for all web content, regardless of site. This option is available in about:preferences under "Language and Appearance" and can be scaled up or down from 100% as needed.
  • Fixed:
  • Improved audio quality when playing back audio at a faster or slower speed.

New in Firefox Developer Edition 72.0b (Jan 20, 2020)

  • New:
  • Firefox’s Enhanced Tracking Protection marks a major new milestone in our battle against cross-site tracking: we now block fingerprinting scripts by default for all users, taking a new bold step in the fight for our users’ privacy.
  • Firefox replaces annoying notification request pop-ups with a more delightful experience, by default for all users. The pop-ups no longer interrupt your browsing, in its place, a speech bubble will appear in the address bar when you interact with the site.
  • Picture-in-picture video is now also available in Firefox for Mac and Linux: Select the blue icon from the right edge of a video to pop open a floating window so you can keep watching while working in other tabs or apps. Learn how the feature works.
  • Changed:
  • Support for blocking images from individual domains has been removed from Firefox, because of low usage and poor user experience.

New in Firefox Developer Edition 71.0b (Jan 20, 2020)

  • New:
  • Firefox has a new command line parameter, --kiosk, that opens Firefox in fullscreen mode
  • Windows users now have the ability to pop out videos on the web into an always-on-top video player using the Picture-in-Picture feature! For most videos, this can be accomplished by hovering the video with the mouse, and clicking on the Picture-in-Picture toggle.
  • Locales added: Catalan (Valencian) (ca-valencia), Tagalog (tl), Triqui (trs)
  • Changed:
  • Redesigned internal configuration page (about:config)
  • A new Certificate Viewer that is easier to use, with more features and more detailed information.

New in Firefox Developer Edition 70.0b1 (Sep 6, 2019)

  • New:
  • The baseline interpreter for JavaScript bytecode execution is now enabled
  • The developer tools accessibility panel now includes an audit for keyboard accessibility
  • The developer tools accessibility panel now includes a color deficiency simulator for systems with WebRender enabled
  • When focused on a toolbar button, users can now type the first (or first few) characters of another button's name to jump directly to that button.
  • An information icon is displayed next to CSS properties that don't have an effect on the current element in the Rules pane of the Page Inspector.
  • Fixed:
  • macOS: Vastly reduced power consumption with a more efficient compositor
  • Changed:
  • Built-in Firefox pages now follow the system dark mode preference
  • WebRender enabled by default for Windows desktops with Integrated Intel graphics for Low Resolution devices
  • Aliased theme properties have been removed, which may affect some themes
  • The Firefox Accounts toolbar menu has been updated and reorganized to give faster access to account features and services.

New in Firefox Developer Edition 67.0b10 (Apr 11, 2019)

  • Easier access to your list of saved logins from the main menu and login autocomplete.
  • We’ve added a toolbar menu for your Firefox Account to provide more transparency for when you are synced, sharing data across devices and with Firefox. Personalize the appearance of the menu with your own avatar.
  • Enable FIDO U2F API, and permit registrations for Google Accounts

New in Firefox Developer Edition 67.0b7 (Apr 1, 2019)

  • Intent to ship: WebRender was enabled by default in Betas since Firefox 64 for Desktop NVIDIA GPUs on Windows 10 and should be released with Firefox 67 in May
  • Firefox 67 willl be able to run different Firefox installs side by side by default.
  • Tabs can now be pinned from the Page Actions menu in the address bar
  • Users can block known cryptominers and fingerprinters in the Custom settings or their Content Blocking preferences
  • The Import Data from Another Browser feature is now also available from the File menu
  • Firefox will now protect you against running older versions of Firefox which can lead to data corruption and stability issues.
  • Fixed:
  • Various security fixes
  • Changed:
  • Firefox no longer supports handling webcal: links with 30boxes.com
  • Change to extensions in Private Windows: Any new extensions you add to the browser won’t work in Private Windows unless you allow this in the settings.
  • Developer:
  • The DevTools Changes panel now supports copying modified CSS. You can either copy the full changes or individual changed rules.

New in Firefox Developer Edition 65.0b4 (Dec 12, 2018)

  • The display language for the Firefox application UI is now changeable in the Options page
  • Added support for the WebP image format
  • Firefox on Windows can now be installed using an MSI installer
  • Firefox now supports Handoff on macOS to continue browsing from your iOS device to your Mac
  • On Linux, tabs can be switched by scrolling in the tab bar
  • Changed:
  • Updated the Content Blocking section in the Privacy & Security Options page and in the Control Center to simplify blocking options for users
  • Enhanced security for Linux, Android, and macOS users via stronger stack smashing protection being enabled by default
  • Firefox can now be set to warn when exiting, even when configured to automatically restore the session on the next launch
  • Memory usage is also now reported for each resource visible in the updated Task Manager page found at about:performance
  • Developer:
  • Added a new Flexbox inspector tool to detect and highlight Flexbox containers and debug Flex items' sizes
  • All CSS changes made in the Rules panel are now tracked in the new Changes tab
  • Added support for the Storage Access API on desktop platforms

New in Firefox Developer Edition 63.0b (Sep 11, 2018)

  • New:
  • On macOS, WebGL power preferences allow non-performance-critical applications and applets to request the low-power GPU instead of the high-power GPU in multi-GPU systems
  • Improved Windows 10 integration: your Firefox theme now matches your OS Dark / Light mode
  • WebExtensions now run in their own process on Linux
  • Faster tab switching in the majority of cases for our macOS users
  • Improved the reactivity of Firefox on macOS
  • Changed:
  • In the Library, the Open in Sidebar feature for individual bookmarks was removed
  • Never check for updates option removed from about:preferences. If a substitute is needed, we recommend using the DisableAppUpdate enterprise policy
  • Firefox now warns about having multiple windows/tabs open when quitting from the main menu.
  • The Ctrl+Tab shortcut now displays thumbnail previews of your tabs and cycles through tabs in recently used order. This new default behavior is activated only in new profiles and can be changed in your preferences
  • The build infrastructure of Firefox on Windows moved to the Clang tool chain, bringing important performance gains
  • Changes for web developers:
  • Developer tools:
  • The Fonts tab in the Page Inspector now includes an editor that makes it easy to view and edit the settings of the fonts on your page.
  • Removals. HTML:
  • Support for the <img> element's decoding attribute has been added (bug 1416328)
  • Removals. CSS:
  • Support for the :defined pseudo-class has been added.
  • Support for row-gap, column-gap and gap has been added in Flexbox layout (bug 1398483).
  • Re-enabled support for webkit-prefixed pixel-density @media queries.
  • Firefox now supports the CSS Flexible Box Layout (Flexbox) properties align-self, align-content, and align-items as well as the justify-content property (bug 1472843).
  • Implemented path() function for offset-path (bug 1429298).
  • Implemented syntax improvements from the Media Queries Level 4 specification (bug 1472843).
  • Swapped values of 2-value overflow syntax so block is first and inline is second (bug 1481866).
  • Renamed offset-* properties to inset-block-start, inset-block-end, inset-inline-start, and inset-inline-end (bug 1464782).
  • Added support for the prefers-reduced-motion media feature (bug 1365045).
  • Added flow relative values (block, inline) for the resize property (bug 1464786).
  • Implemented flexbox layout for safe & unsafe values in align-self, align-content, and justify-content (bug 1297774).
  • The logical properties (where appropriate) are now animatable (bug 1309752).
  • Removals:
  • Removed offset-block-start, offset-block-end, offset-inline-start and offset-inline-end; these have been renamed as described above (bug 1464782).
  • SVG:
  • No changes
  • Removals. JavaScript:
  • The Symbol.prototype.description property has been implemented (bug 1472170).
  • The Object.fromEntries method has been added (bug 1469019).
  • Removals:
  • Experimental WebAssembly Module IndexedDB serialization support has been removed (bug 1469395).
  • APIs. New APIs:
  • The Shadow DOM (bug 1471947) and Custom Elements (bug 1471948) APIs have been enabled by default; See Web components for more details.
  • The Media Capabilities API been implemented.
  • The Async Clipboard API has been implemented and enabled by default for all channels. As is the case with Chrome, Firefox currently implements only the writeText() and readText() methods; however, unlike Chrome, readText() is only available in browser extensions.
  • The SecurityPolicyViolationEvent interface is now supported. It allows sending events when the Content-Security-Policy is violated (bug 1472661).
  • APIs. DOM:
  • The following portions of the Web Animations API have been enabled by default:
  • The Animation properties ready and finished, specifying the Animation object's ready and finished Promises.
  • The Animation object's effect property.
  • The interfaces KeyframeEffect and AnimationEffect.
  • The Element.toggleAttribute() method has been implemented (bug 1469592).
  • The Payment Request API paymentmethodchange event has been implemented, along with its implementing PaymentMethodChangeEvent interface. This event is sent to PaymentRequest objects when changes are made to the payment method selected within the current payment handler, such as when the user selects a different credit card to use when paying by Apple Pay (bug 1468356).
  • The obsolete and non-standard Firefox-only methods Window.back() and Window.forward() have been removed. Please use the window.history.back() and window.history.forward() methods instead (bug 1479486).
  • Firefox now supports the asynchronous clipboard methods Clipboard.readText() and Clipboard.writeText(). The read() and write() methods have also been implemented but currently work exactly the same as their text-only counterparts (bug 14614645).
  • The historical, previously non-standard, Event.returnValue property is now supported by Firefox for compatibility purposes (bug 1452569).
  • Implemented the Window.event property to improve web compatibility, now that it's become standard (bug 218415).
  • To bring Firefox into alignment with Edge and Chrome, the navigator.platform property now returns "Win32" even when running on 64-bit Windows (bug 1472618).
  • Prior to Firefox 63, links that open new windows that had rel="noopener", as well as calls to Window.open() with the noopener window feature enabled would default to having all window features disabled, so that you had to explicitly re-enable any standard features you wanted. Now these windows have the same set of features enabled as any other window, and you need to explicitly turn off any you don't want (bug 1419960).
  • DOM events:
  • Handling of the Alt key on the right side of the keyboard has been improved on Windows. If the user's current keyboard layout maps the Alt key to the AltGr modifier key, the value of KeyboardEvent.key is now reported as "AltGraph". This behavior matches that recently introduced into Chrome (bug 900760).
  • Service workers:
  • The createObjectURL() and revokeObjectURL() methods are no longer available on ServiceWorker instances due to the potential they introduced for memory leaks to occur (bug 1264182).
  • Media, Web Audio, and WebRTC:
  • Microphone access now works simultaneously in multiple tabs, even within the same content process. This improvement applies to the regular version of Firefox as well, though web developers were probably most likely to run into this (bug 1404977).
  • RTCDataChannel has been updated to support the sctp-sdp-21 data format for the data, in addition to the older sctp-sdp-05 format previously supported.
  • Since it was deprecated in the specification anyway, the limited support for Doppler effects on PannerNode has been removed from the Web Audio API. The AudioListener properties dopplerFactor and speedOfSound have been removed, along with the PannerNode method setVelocity() (bug 1148354).
  • The ConstantSourceNode node type for Web Audio API now has a default channel count of 2 rather than 1, in order to match the specification (bug 1413283).
  • The Web Audio API interface AudioScheduledSourceNode (and by extension, all the other node types based on it) now throw the correct exception when a negative value is specified for the node start time. That error is RangeError (bug 1413284).
  • The minimum and maximum permitted values for an AudioParam object's value have been changed to the minimum negative single-precision floating-point value (-340,282,346,638,528,859,811,704,183,484,516,925,440) and the maximum positive single-precision floating-point value (+340,282,346,638,528,859,811,704,183,484,516,925,440), respectively (bug 1476695).
  • The {domxref("SourceBuffer.changeType")}} method, which allows changing codecs during an active stream, has been enabled by default. This is part of the Media Source Extensions API (bug 1481166).
  • The AudioParam.setValueCurveAtTime() method has been updated to correctly accept an array of floating-point values to indicate the parameter's values to change to over time. Previously, it was requiring a Float32Array (bug 1421091).
  • AudioParam.setValueCurveAtTime() has also been updated to correctly return a proper TypeError when a non-finite value is found in the values array (bug 1472095).
  • In addition, setValueCurveAtTime() has been updated to ensure that when the parameter finishes following the specified value curve after the duration elapses, the value of the parameter is set to the last value in the list of values to curve through (bug 1308436).
  • The RTCRTPStreamStats dictionary has been renamed to RTCRtpStreamStats for consistency with the other dictionaries and the specification (bug 1480498).
  • The RTCRtpStreamStats dictionary's isRemote property is deprecated and will be removed in Firefox 65. A warning is now output to console when this property is accessed. See this blog post on the Advancing WebRTC blog for details (bug 1393306).
  • Canvas and WebGL:
  • A new powerPreference context attribute has been added to HTMLCanvasElement.getContext(). On macOS this allows WebGL non-performance-critical applications and applets to request the low-power GPU instead of the high-power GPU in multi-GPU systems (bug 1349799).
  • Removals. CSSOM:
  • No changes
  • Removals. HTTP:
  • The Clear-Site-Data header is implemented and no longer behind a preference (bug 1470111).
  • Removals. Security:
  • Site favicons are now subject to Content Security Policy, if one is configured for the site (bug 1297156).
  • Firefox now recognizes the CSP script-src directive's 'report-sample' expression when generating violation reports. This directive indicates that a short sample of where the violation occurred should be included in the report. Previously, Firefox always included this sample (bug 1473218).
  • Removals. Plugins:
  • No changes
  • Removals. Other:
  • Corrected the behavior of PerformanceObserver.observe() to simply do nothing if no valid entry types are found in the specified array of entry types to observe, or if the array is empty or missing. Previously, Firefox was incorrectly throwing a TypeError (bug 1403027).
  • Changes for add-on developers:
  • API changes:
  • A "search" API was added to retrieve the installed search engines.
  • Added menus.getTargetElement() to the menus API. The method returns the element referenced by the targetElementId parameter (bug 1325814).

New in Firefox Developer Edition 62.0b6 (Jul 6, 2018)

  • New:
  • Display preview image and favicon in the New Bookmark dialog
  • Added a Clear Site Data and Cookies button to the identity popup located next to the address bar so as to provide a quick and easy process to delete local data for the visited website
  • Three-pane Inspector in Developer Tools separates the rules into its own panel
  • New tab page sections such as top sites, highlights, and Pocket can be adjusted to include 1 to 4 rows in the Preferences
  • Added Canadian English (en-CA) locale
  • Users who disconnect Firefox for desktop from Sync are now offered the option to wipe their personal data from that device (such as bookmarks, passwords, history, cookies, and site data)
  • Added a button to the hamburger menu to toggle Tracking Protection on and off
  • Changed:
  • The description field for bookmarks has been removed Users who manually changed the field can export old descriptions via html or json Stored descriptions will be removed in a future release

New in Firefox Developer Edition 62.0b4 (Jun 29, 2018)

  • New:
  • Display preview image and favicon in the New Bookmark dialog
  • Added a Clear Site Data and Cookies button to the identity popup located next to the address bar so as to provide a quick and easy process to delete local data for the visited website
  • Three-pane Inspector in Developer Tools separates the rules into its own panel
  • New tab page sections such as top sites, highlights, and Pocket can be adjusted to include 1 to 4 rows in the Preferences
  • Added Canadian English (en-CA) locale
  • Users who disconnect Firefox for desktop from Sync are now offered the option to wipe their personal data from that device (such as bookmarks, passwords, history, cookies, and site data)
  • Added a button to the hamburger menu to toggle Tracking Protection on and off
  • Changed:
  • The description field for bookmarks has been removed. Users who manually changed the field can export old descriptions via html or json. Stored descriptions will be removed in a future release.

New in Firefox Developer Edition 61.0b5 (May 15, 2018)

  • New:
  • Performance Enhancements:
  • Quantum CSS improvements which improve page rendering times
  • Improved page rendering speed with the new retained display list feature
  • Faster switching between tabs on Windows and Linux
  • On-by-default support for the latest draft of the TLS 1.3 specification
  • Various improvements for dark theme support will provide a more consistent experience across the entire Firefox UI
  • Added the ability to share current the URL with MacOS sharing providers from the Page Actions menu
  • OpenSearch plugins offered by web pages can now be added from the page action menu for easier installation
  • Improved support for allowing WebExtensions to manage and hide tabs
  • Changed:
  • The settings for customizing your homepage and new tab page in Firefox have been moved to a new Preferences section, Home. It can be accessed from the sidebar in Preferences or by visiting about:preferences#home
  • In order to improve user security, access to FTP subresources inside http(s) pages has been blocked
  • Developer:
  • he settings for customizing your homepage and new tab page in Firefox have been moved to a new Preferences section, Home. It can be accessed from the sidebar in Preferences or by visiting about:preferences#home
  • In order to improve user security, access to FTP subresources inside http(s) pages has been blocked

New in Firefox Developer Edition 60.0b12 (Apr 13, 2018)

  • new
  • The policy engine is now available to customize Firefox deployments in Enterprise environments (more details on https://wiki.mozilla.org/enterprise)
  • Added support for Web Authentication, allowing the use of USB tokens for authentication to web sites
  • Locale added: Occitan (oc)
  • The new CSS engine introduced in Firefox Quantum (57.0) is now used for the browser's user interface, in addition to web content.
  • fixed
  • Various security fixes
  • changed
  • On Windows, the shortcut for entering Reader View has changed to F9, for better compatibility with keyboard layouts which use AltGr.
  • It is no longer possible to have multiple bookmark keywords for the same url, unless the request has different POST data.
  • Enhanced camera privacy indicators: Firefox now turns off your camera when you face-mute on web-sites that use your camera, turning off your camera light so you don't have to wonder if the site is still recording you. The light will come back on whenever recording resumes.

New in Firefox Developer Edition 60.0b (Mar 20, 2018)

  • New:
  • The policy engine is now available to customize Firefox deployments in Enterprise environments (more details on https://wiki.mozilla.org/enterprise)
  • Added support for Web Authentication, allowing the use of USB tokens for authentication to web sites
  • Locale added: Occitan (oc)
  • The new CSS engine introduced in Firefox Quantum (57.0) is now used for the browser's user interface, in addition to web content.
  • Changed:
  • On Windows, the shortcut for entering Reader View has changed to F9, for better compatibility with keyboard layouts which use AltGr.
  • It is no longer possible to have multiple bookmark keywords for the same url, unless the request has different POST data.
  • Enhanced camera privacy indicators: Firefox now turns off your camera when you face-mute on web-sites that use your camera, turning off your camera light so you don't have to wonder if the site is still recording you. The light will come back on whenever recording resumes.
  • Developer:
  • Responsive Design Mode now offers explicit control over whether the page should reload.
  • Developers can now use promises within IndexedDB transactions
  • Fixes:
  • Various security fixes

New in Firefox Developer Edition 59.0 (Jan 29, 2018)

  • New:
  • For users with the unified search bar, search suggestions will appear ahead of browsing history by default. This can be changed in Settings on Windows and in Preferences on Linux and MacOS.
  • Added new settings in about:preferences that allow you to stop intrusive websites from asking you to receive notifications or access advanced device features such as camera and geolocation, while still allowing websites you trust to use these features.
  • Added locale: Interlingua (ia)
  • Changed:
  • Changed the location of Firefox Health Report from about:healthreport to about:telemetry

New in Firefox Developer Edition 58.0b2 (Nov 10, 2017)

  • New:
  • WebVR has been enabled for Mac OS X users
  • Added Nepali (ne-NP) locale
  • Added support for form autofill for credit card
  • Changed:
  • Downgrading profile to previous versions is not supported. In case of downgrade, it is suggested to use a new profile

New in Firefox Developer Edition 57.0b3 (Sep 29, 2017)

  • NEW:
  • Firefox is getting a major Visual Redesign (Photon project) activated on the Nightly channel and which will ship with Firefox 57 on the release channel.
  • Allow users to manage the site data
  • Added support for Date/Time input
  • Accessibility indicator will now appear in the title bar of the window when Accessibility services are enabled
  • Changed:
  • Support more strict sandboxing protection (level 3) on Linux
  • The browser's "autoscrolling" feature now uses asynchronous scrolling, similar to other input methods like mousewheel, providing a smoother scrolling experience.
  • Middle mouse paste in the content area on Unix systems no longer navigates to URLs by default